Kuroshio Shape Composition and Distribution of Filamentous Diazotrophs in the East China Sea and Southern Yellow Sea

Jiang, Zhibing; Chen, Jianfang; Zhai, Hongchang; Zhou, Feng; Yan, Xiaojun; Zhu, Yuanli; Xuan, Jiliang; Shou, Lidan; Chen, Quanzhen

doi:10.1029/2019jc015413

Cited by 14 publications

(23 citation statements)

References 80 publications

(252 reference statements)

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“…Specifically, we observed that nutrient concentrations and structure play important roles in regulating phytoplankton biomass, especially for diatoms and dinoflagellates, as revealed by the significant positive correlations between PB (and brassicasterol and dinosterol) and DIN (and DIN/DIP and DIN/Si) (Figure 4). This result is consistent with previous findings in the CRE, the ECS and the southern YS in summer (Jiang et al, 2015;Wu et al, 2016), because sufficient nutrients from the Changjiang River induce high phytoplankton biomass in these areas, and the runoff of the Changjiang River is much higher in summer, with the large influencing area of the CDW and forming the fronts beyond 125 • E and 33 • N (Figure 3E; Wei et al, 2015;Jiang et al, 2019b). In contrast, C 37 alkenones showed significant negative correlations with nutrients and temperature, but positive ones with salinity and depth (Figure 4).…”

Section: Spatial Distribution Of Marine Lipid Biomarkerssupporting

confidence: 93%

The Sources and Burial of Marine Organic Carbon in the Eastern China Marginal Seas

Cao

Wang

et al. 2022

Front. Mar. Sci.

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The ecological functions and biogeochemical processes of continental marginal seas are important for the global carbon cycle. In the eastern China marginal seas (ECMS), phytoplankton productivity has increased significantly in recent decades, but the sources and burial processes of marine organic carbon (OC) remain under-studied. We analyzed the contents of marine lipid biomarkers (brassicasterol, dinosterol, and C37 alkenones) in surface suspended particles obtained from seven cruises between 2010 and 2015, and in surface sediments from eight cruises between 2006 and 2012 in the ECMS, to estimate marine OC sources and burial. The correlations between lipid biomarkers and environmental factors were quantified to reveal controlling factors. The study area was divided into four regions according to cluster analysis conducted based on sediment parameters. Our results showed that the concentrations of marine lipid biomarkers in surface water were high near large estuaries such as the Changjiang River Estuary and the Yellow River Estuary, but those in surface sediments were high in mud areas. Nutrient concentration was a key factor controlling phytoplankton biomass in surface water, with high nutrients enhancing the growth of diatoms and dinoflagellates, while haptophytes were more abundant in low-nutrient, high-salinity and cold environments. High marine OC contents calculated from total OC δ13C were mainly associated with fine sediments transported by coastal currents, and finally deposited in mud areas. The proto-burial efficiency of marine OC in the ECMS (7–19%) was markedly higher than the mean value in global marginal seas, with high values being located in the western coast of the ECMS. The proto-burial efficiency of total marine lipid biomarkers (6–24%) was quantified for the first time in our study, with overall values and spatial patterns similar to that of marine OC. A key parameter for marine OC and marine biomarker proto-burial efficiency was sediment grain size. The smaller the sediment grain size was, the better the marine OC and marine biomarker were retained. Our study provides an important basis to elucidate spatial distribution patterns and forcing mechanisms of marine OC in surface water (production process) and surface sediments (burial process), and to estimate carbon budgets in large marginal seas.

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Section: Spatial Distribution Of Marine Lipid Biomarkerssupporting

confidence: 93%

The Sources and Burial of Marine Organic Carbon in the Eastern China Marginal Seas

Cao

Wang

et al. 2022

Front. Mar. Sci.

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“…Our result revealed slightly higher NFR on the surface than at the 10% light depth (∼5–45 m with 100–250 μmol quanta m −2 s −1 ). This result was highly supported by the abundant filamentous diazotrophs in upper 45 m (Jiang et al., 2019) as well as their high adaptability to this relatively low light environment (Lu et al., 2018; Villareal, 1990). Previous studies also showed relatively low variability in NFRs throughout the euphotic zone, except for 1% of the surface irradiance, such as the ECS (Zhang et al., 2012) and Northwestern Atlantic Ocean (Capone et al., 2005).…”

Section: Discussionmentioning

confidence: 89%

“…Because they are close to the mainland, high terrestrial inputs of P and Fe are observed therein compared with the open ocean (Jickells et al., 2005; Martiny et al., 2019), probably resulting in an alleviation of P and Fe limitation of diazotrophs (Shiozaki et al., 2014). Particularly diazotrophic cyanobacteria Trichodesmium (Capone et al., 1997), frequently occurs and occasionally blooms in western boundary currents, including the Gulf Stream (Palter et al., 2020), Brazil Current (Detoni et al., 2016), East Australian Current (Armbrecht et al., 2015), and Kuroshio (Jiang et al., 2019; Jiang, Li, et al., 2018; Shiozaki, Takeda, et al., 2015). Western boundary currents seem to be hotspots of marine N 2 fixation (Shiozaki et al., 2010; Tang et al., 2019).…”

Section: Introductionmentioning

confidence: 99%

Enhancement of Summer Nitrogen Fixation by the Kuroshio Intrusion in the East China Sea and Southern Yellow Sea

et al. 2023

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The western boundary currents are characterized by abundant diazotrophs including Trichodesmium, which may fuel N2 fixation when they intrude into marginal seas. The Kuroshio, a western boundary current in the North Pacific, flows into the East China Sea (ECS) and southern Yellow Sea (SYS), which transports abundant Trichodesmium and diatom‐diazotroph associations (DDAs). Additionally, low nitrogen:phosphorus (N:P) ratio and relatively abundant dissolved iron have been observed in the offshore ECS because of the Kuroshio intrusion as well as riverine/atmospheric inputs of P and iron. We hypothesized that the intrusion of Kuroshio greatly enhanced N2 fixation in the ECS and SYS. N2 fixation rates (NFRs) were measured using a 15N2 bubble method during summer 2013. The surface and depth‐integrated NFRs in the ECS and SYS were 1.45 nmol N L−1 d−1 and 81.7 μmol N m−2 d−1 on average, respectively, with the highest values of 13.84 nmol N L−1 d−1 and 511.8 μmol N m−2 d−1. We found that NFRs were significantly higher in the ECS oceanic (Kuroshio water) and mesohaline regions (Kuroshio‐affected water) than in the SYS and the ECS low‐salinity and coastal upwelling regions. NFR was significantly positively correlated with the densities of Trichodesmium and DDAs, salinity, and temperature but was negatively with NO3− and N:P ratio. Generalized additive models confirmed that spatial variation in NFR was overwhelmingly contributed by Trichodesmium density. These findings suggested that the Kuroshio intrusion significantly enhanced N2 fixation in the ECS through promoting growth of filamentous diazotrophs and providing appropriate nutrient environment.

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“…For example, some Calothrix phylotypes were positively correlated with both salinity and HM, as well as low N ( Supplementary Figure S5B1 ). Jiang et al (2019) also noted positive correlations between Calothrix and these soil properties, and suggested that these cyanobacteria likely play an important role in suppling N in habitats with low N fertility. Others have also noted that Sphingomonas spp.…”

Section: Discussionmentioning

confidence: 87%

Diversity and functional traits of indigenous soil microbial flora associated with salinity and heavy metal concentrations in agricultural fields within the Indus Basin region, Pakistan

et al. 2022

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Soil salinization and heavy metal (HM) contamination are major challenges facing agricultural systems worldwide. Determining how soil microbial communities respond to these stress factors and identifying individual phylotypes with potential to tolerate these conditions while promoting plant growth could help prevent negative impacts on crop productivity. This study used amplicon sequencing and several bioinformatic programs to characterize differences in the composition and potential functional capabilities of soil bacterial, fungal, and archaeal communities in five agricultural fields that varied in salinity and HM concentrations within the Indus basin region of Pakistan. The composition of bacteria with the potential to fix atmospheric nitrogen (N) and produce the enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase were also determined. Microbial communities were dominated by: Euryarchaeota (archaea), Actinobacteria, Proteobacteria, Planctomycetota, Firimicutes, Patescibacteria and Acidobacteria (bacteria), and Ascomycota (fungi), and all soils contained phylotypes capable of N-fixation and ACC-deaminase production. Salinity influenced bacterial, but not archaeal or fungal communities. Both salinity and HM altered the relative abundance of many phylotypes that could potentially promote or harm plant growth. These stress factors also appeared to influence the potential functional capabilities of the microbial communities, especially in their capacity to cycle phosphorous, produce siderophores, and act as symbiotrophs or pathotrophs. Results of this study confirm that farms in this region are at risk due to salinization and excessive levels of some toxic heavy metals, which could negatively impact crop and human health. Changes in soil microbial communities and their potential functional capabilities are also likely to affect several critical agroecosystem services related to nutrient cycling, pathogen suppression, and plant stress tolerance. Many potentially beneficial phylotypes were identified that appear to be salt and HM tolerant and could possibly be exploited to promote these services within this agroecosystem. Future efforts to isolate these phylotypes and determine whether they can indeed promote plant growth and/or carry out other important soil processes are recommended. At the same time, identifying ways to promote the abundance of these unique phylotypes either through modifying soil and crop management practices, or developing and applying them as inoculants, would be helpful for improving crop productivity in this region.

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Kuroshio Shape Composition and Distribution of Filamentous Diazotrophs in the East China Sea and Southern Yellow Sea

Cited by 14 publications

References 80 publications

The Sources and Burial of Marine Organic Carbon in the Eastern China Marginal Seas

The Sources and Burial of Marine Organic Carbon in the Eastern China Marginal Seas

Enhancement of Summer Nitrogen Fixation by the Kuroshio Intrusion in the East China Sea and Southern Yellow Sea

Diversity and functional traits of indigenous soil microbial flora associated with salinity and heavy metal concentrations in agricultural fields within the Indus Basin region, Pakistan

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